Process for treating coal



Filed Dec. 2l. v1936 mmb m/ @5% mwxkw QS.

@n QH w Patented June 15,1939

PATENT OFFICE 2,162,064 rRocEss Foa HEATING coAL Maurice D. Curran, Glendale, Mo., assigner to Tar & Petroleum Process Company, Chicago, lll., a corporation of Illinois Application December 21, 1936, Serial No. 111,032

3 Claims.

The present invention relates to improvements in processes for treating coal.

More particularly the present invention relates to a process of utilizing the partially devolatilized 5 coal which results from the practice of certain coke making processes.

In certain of its aspects the present invention is analogous in certain respects to the invention disclosed and claimed in application Serial No.

134,552, filed April 2, 1937, which is in part a continuation of application Serial No. 91,325, led July 18, 1936, by the present applicant.

In the application referred to, the coking process is carried out in the Knowles type of oven, l5 an example of which is illustrated and described in the patent to Knowles and McIntyre No. 1,635,280, patented July 12, 1927. According to the type of oven referred to, coal or equivalent material is disposed on a horizontal floor heated 20 by iiues extending beneath said floor, the coking floor forming a part of the coking chamber, the oven having means for charging coal, means for withdrawing vapors and gases, means for sealing the ends of the chamber, and means permitting 25 the pushing of the resulting coke out of the coking chamber. According to the method referred to in said application, the layer of coal or equivalent material is shallow relative to the width thereof. y

According to the method of coking in which the bed of coal or its equivalent is shallow compared to its width and in which the heat is applied below the bed of coal or the like, vapors of distillation, water vapors andiixed gases from the coal adja- 35 cent to the bottom of said bed are liberated at the beginning of the coking period, a substantialportion of these vapors and gases passing upward through the coal and imparting their heat to the cooler coal mass. 'I'his results, rst, in 40 the vaporization of water in the coal, and then in vaporization of volatile matters and subsequent partial condensation of the vapors provided the temperature in the upper portion of the charge is sufliciently low, followed by redistillation and 45 elimination from the coal mass as-the coking process proceeds. The passage of vapors and gases through the coal mass results in a transfer of heat, by means of convection, tothe coal mass and an increased thickness of the coking zone 50 which may attain a thickness of two inches or more in the case of coals having a high coking of the thickened coking zone leads to an unusually porous structure in the coke which in turn increases the reactivity of the coke to oxygen, and, lother things being equal, increases combustibility. `The upper part of the charge is very con- 5 siderably devolatilized but is not suciently coked to form a hard coherent mass.

An object of the present invention is to provide a method which will provide a material readily applicable to a briquetting process.

A further object is to provide a method of removing the moisture and a portion of the-volatile matter in coal so that such coal can be made into briquettes which will burn with very little smoke. j

A further object is to provide a method for removing the moisture and a portion of the volatile matter in coal while it is being treated in a commercial coking process, so that such coal can be made into briquettes without the aid of added Av binders, which briquettes Will burn with very little smoke.

A further object is to provide a method for removingfrom coal the moisture and a portion of the volatilev matter which distills off at temperatures below the softening temperature of the coal, while using a commercial coking process so that such coal can be made into briquetteswith or without the use of added binders-which, will burn with very little smoke.

A further object is to utilize the heat available in hot gases distilled from coal in a coke making process in a Knowles type of oven to remove the moisture and a portion of the Ivolatile matter in the coal forming the upper part of the coal charge so'that such partially devolatilized coal can be made into briquettes-With or Without the aid of added binders-which will burn with very little smoke.

A further object is to provide an improved 40 coking process which will remove the moisture and a part of the volatile matter, including the lower boiling tar oils which are liberated when coal s heated to temperatures just under the softening temperature of such coal, so that such partially devolatilized coal can be made into briquetteswith or without the use of added binders, which briquettes will burn with very little smoke.

A'further object is to provide a commercial 50 coking process to produce two types o f smokeless domestic fuel, namely coke and smokeless briquettes, by carrying on the distilling operation in said coking process so that the lower portion of the coal charge will be converted to so-called 50 bottom of the charge toward the top to the point where the upper part of the charge is considhigh temperature coke in such a-way that some of the products of distillation are utilized to heat the coal in the upper part of the charge to the point where all the free moisture and a portion of the volatile matter in such coal will be distilled o'if so that such coal, when made into briquettes, will burn with very little smoke.

A further object is to provide a method which will remove the low boiling' tar oils which are distilled off when coal is heated for a comparatively long time (6 to 12 hours) at temperatures below the softening temperature of the coal so that such coal can be formed into strong briquettes-with or Without the aid of added binders-Which will burn with very little smoke.

A further object is to provide a method which will remove from coal a part of those lower boiling tar oils and the accompanying volatile combustible matter which are known to be the principal causes of smoky combustion, and which are distilled oil' when coal is heated to temperatures just under the softening temperature of the coal,

' in said partially devolatilized coal.

vso that such coal can be compressed into briquettes-with or without the use of added binders-which will burn with very little smoke.

A'further object is to provide a method which will remove from coal a part of those lower boiling tar oils and the accompanying volatile combustible matter which are known to be the principal causes of smoky combustion, and which are distilled off when coal is heated to temperatures `under the softening temperature yof the coal, so

the partially devolatilized coal is conducted to the briquetting press and `how the commercial coke may be delivered to a car.

As noted in the -application above referred to, the process of coking is carried on from the erably devolatilized but is not sufficiently coked to form a hard coherent mass. 55'

Ainches of hot, partially devolat'ilized. but unfused coal will remain on thetop of thecoke substance when the charge is pushed from the oven. During theprocess of coking, the material inthe lower portion of the bed', the moisture and a part of the volatile matter including the lower boiling tar oils will be liberated from the upper part of said bed. The temperature conditions may be maintained in said upper part of the bed at a value below the softening temperature'thereof, This partially devolatilized coal-is separated from the coke substance preferably while hot and before quenching. Said partially devolatilized'coal is charged directly to a briquetting press preferably while it is still hot, where it will be formed into good solid briquettes without the use of any binder except those' tarry substances remaining Said briquettes will burn with very little smoke.

. 2. The method of producing material suitable No difficulty need be encountered in preserving the temperature of the partially devolatilized coal after it has been pushed from the coking chamber up to the point where it is formed into the briquettes. By utilizing conveyors, tram cars, lorries, or other means of conveyance, whichmay be properly insulated, the hot devolatilized coal can be delivered tothe briquetting presses without substantial heat loss I j Furthermore, oxidation of the hot devolatilized 10 coal may be avoided by handling the hot coke and partially dev olatilized coal in an atmosphere of y steam, water vapor, or other non-combustible gas.

It will be understood that the temperature of and/or the amount and character of the tarry matter in the hot, partially devolatilized coal within the coking chamber can be controlled by regulation of the charge and the heat treatment given in the oven so that said partially devolatilized coal can be delivered to the briquetting presses at any desired temperature and/or with the desired content of volatile substances, said temperature being either above or below the softening temperature of the coal. The temperature is limited on the one -side by the softening point 'of the coal which must not be exceeded and on the other side by a sufficiently high temperature to drive olf practically all of the moisture and a considerable proportion of the volatile matter, 30 the volatile matter driven off containing substantially all of the smoke producing portion of the volatile matter of the original coal.V Thus the briquettes finally produced are substantially smokeless.

It need not be explained further that by utilization of the steps above described the objectshere-` inabove recited will be attained.

Though a preferred processA has been described in detail, many modifications will occur to those skilled in the art. It is intended to cover all such modifications that fall within the scope of the appended claims. 'r f 1. The process of treating high volatile, cokable coal which consists in providing a bed of coal shallow relative to its width and. length, applying heat thereto below said bed, stopping the coking process at a point which will produce a pre,- determined amount of partially devolatilized coal on the top of the coke, which partially devolatilized coal has its moisture driven off and those volatiles removed which distill off at temperatures below the softening temperature of said high volatile, cokable coal, separating said partially devolatilized coal from the coke in said charge, and, while said partially devolatilized coal is hot, pressing` it into briouettes.

for combustible briquettes and for producing commercial coke which consists in heating a bed of high volatile, cokable coal shallow relative to its width and length, the heat being applied substantially entirely from below, carrying said process to a vpoint where the lower portion of said bed is converted Yinto coke while freeing the upper portion of said becl from moisture and a portion of the low boiling tar oils and volatile matter therein, and thereafter separating said partially devolatilized coal from saidV coke and while the contents of said upper portion are still hot pressing said contents into briquettes.

3. The method of treating coal which consists l in heating a bed of high volatile, cokable coal,

mesme the heat being applied from below, proceeding with this step until the lower portion of said bed is converted into coke while removing a large part of the moisture and low-boiling tar oils and volatile combustible matter from the upper portion of said bed, separating said coke from the material in the upper portion of said bed, the temperature in the upper portion of said bed being maintained under the softening temperature of the coal, vand pressingthe contents of said upper portion while still hot into briquettes.

MAURICE D. CURRAN. 

